Field of the Invention and Related Art
The present invention relates to a developer cartridge for supplying developer to an image forming apparatus utilizing a process for forming an electrostatic latent image and developing the same, such as an electrophotographic copying machine, electrophotographic laser beam printer and the like.
In an image forming apparatus utilizing an electrophotographic process, it is necessary to visualize an electrostatic latent image formed on an image bearing member by developer (toner) in a developing device. The toner should be replenished to the image forming apparatus at need, and such replenishment of the toner is sometimes effected by the use of a developer cartridge wherein an opening is sealed by a sealing member. The developer cartridge can supply the developer contained therein to the image forming apparatus through the opening, by freeing or opening the opening by peeling the sealing member from the opening after the developer cartridge has been mounted on a predetermined position in the image forming apparatus.
Explaining an example of the developer cartridge of this kind with reference to FIG. 1, a developer cartridge 100 comprises a box-like container 110 having a longitudinal opening 111 and containing developer therein, and a sealing member 120 adhered to an adhesion portion 112 formed around the opening 111 of the container 110 to seal the container 110. The sealing member 120 is folded back along a folding line 121, and a gripping portion 122 of the folded portion is positioned to the end portion (right side in FIG. 1) of the container 110. When an operator pulls the gripping portion 122 of the sealing member 120 in a direction P shown by &he arrow to peel the sealing member 120 from the adhesion portion 112 of the container 110, the opening 111 is exposed, whereby the toner in the developer cartridge 100 can be easily taken out.
The peeling force for the sealing member 120 is closely related to the configuration of the adhesion portion 112, and the longer the dimension of the adhesion portion 112 perpendicular to the peeling direction (direction P), the larger the peeling force. In many cases, as shown in FIG. 1, since the configuration of the opening 111 of the developer cartridge 100 is generally rectangular, the configuration of the adhesion portion 112 is also generally rectangular along the opening 111. Accordingly, in the case of the prior art shown in FIG. 1, when the sealing member 120 is peeled from the container 110, generally, a large force will be required at the start and the end of the peeling operation.
However, at the end of the peeling operation for the sealing member 120, since the resistance is extinguished suddenly, the cartridge moves or vibrates suddenly due to the reaction with the result that the toner in the cartridge flows out to smear the surroundings, or the sealing member 120 is suddenly pulled toward the operator's hand with the result that the sealing member 120 peeled off and attaching the toner is contacted or adhered to the operator's hand or clothing, thus smearing them.
In order to eliminate such disadvantage, a technique that the sealing member is wound around a take-up member has been proposed as disclosed in the Japanese Patent Laid-open No. 60-41068. However, in this case, the arrangement is complicated, the number of parts is increased to worsen the productivity, and the manufacturing cost is also increased.
Further, a method in which the sealing member is not completely peeled off from the container and adhered partly to the latter can be adopted or used. However, in this case, it is difficult to use the developer cartridge in the case where the developer is replenished into a developing device of a process cartridge having a photosensitive member, chargers and the developing device are insertable into an image forming apparatus as disclosed in the Japanese Patent Laid-open No. 59-13262 or in the case where the developer cartridge is maintained within an image forming apparatus after it has been opened and rotated as disclosed in the Japanese Patent Laid-open No. 60-87371.